Insulation board



Patented Aug. 26, 1952 No Drawing. Application December 19, 1944, Serial No. 568,941

Claims.

The invention relates to improvements in nbrous building material and processes for making the same. More particularly, it relates to the production of an inexpensive improved fibrous insulation and building board having great strength and excellent insulating qualities.

As a basic material for the formation of the boards of the invention, the shives forming the waste material after decorticating flax and hemp stalks and the like are of particular advantage. Ordinarily, before the decorticating of flax and hemp and other bast fiber plants, the stalks are exposed to the weather or soaked in water in order to facilitate the removal of the bast fibers for spinning and other purposes. This process is known as retting and in the course of the process there is a considerable loss of plant juices containing many of the constituents both of the bark and the shives. Among these constituents so lost in great part are pentosan and furfural, and also natural resins, all of which are of particular importance as natural binding material in the formation of the boards.

In the manufacture of the board of the present invention, it is a particular object to utilize these natural binders and it is, therefore, desirable that the shives or woody portion of the plant used for the purpose should be derived from unretted stalks of flax and hemp and other bast fiber plants and grasses. At the present time, processes are known for decorticating flax and hemp without retting and the shives resulting from these processes contain practically all the furfural and pentosan and also cellulose and lignin as well as the resinous materials of the natural stalks. Flax and hemp shives, for instance, are very similar in chemical composition. Analysis shows the following percentages:

Flax Hemp Resins 3. 58 2. 85 Furiural 14. 07 14. 18 Penm an 24.01 24.16 Pure Cellulose 37. 05 40. 57

broken up or otherwise processed beyond what takes place in the decorticating machinery, where it is desired to produce a finer grained board, the shives may be cut, shredded or ground.

The material, with an adequate amount of water to float the same, is put into heaters and reduced to a pulp of somewhat coarser nature than would be used for making the better grades of paper. It is reduced in the heaters to about the condition of half stock at a temperature of about to F.

The pulp may be then spread to a predetermined thickness on a screen and is then pressed to squeeze out a large proportion of the water contained therein, and the body so formed is then subjected to pressure of about 100-200 lbs. per square inch while it is heated to a temperature of about 150 to 200 F. and the board is pressed to its final thickness, precautions being taken to prevent lateral expansion thereof. It is then placed in a drier and dried at a temperature of about 200 to 250 F. During this process the natural binding materials in the shives are released and permeate the entire board and the pressure and heating are maintained until the board is practically dry, the heat and pressure being maintained until all danger of warping is past. A smooth, strong board results that can be used as a wall board or interior woodwork or as heat insulation in a building or in refrigerators, as desired.

Having thus described my invention, what I claim is:

1. A composition of matter consisting of woody material derived from the shives of unretted bast fiber plants containing substantially all the natural content of pentosan and furfural-yielding material and pressed under heating into the form of an insulating and building board.

2. An insulation and building board composed of untreated hemp shives containing substantially all the pentosan and furfural-yielding material of such shives as a bonding material and formed under heat and pressure.

3. An insulation and building board composed of hemp shives containing substantially all of the natural pentosan and furfural-yielding material of said shives and formed under conditions of moisture, heat and pressure.

4.- An insulation and building board consisting of a strong, stiff body of woody material composed of the shives or unretted flax containing substantially all the pentosan and furfuralyielding material of said shives as a bonding material.

5. An insulation and building board consisting of the shives of unretted flax containing substantially all the pentosan and furfural-yielding material of said shives as a binder for the fiber of said unretted flax.

MARGARET E. MUELLER.

, REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Number Number Name Date 908,681 Lappen Jan. 5, 1909 1,108,155 Ellis Aug. '25, 1914 1,503,211 Shaw July 29, 1924 Name Date Hinde Apr. 5, 1927 Vogt June 18, 1929 Sweeney May 5, 1931 Sweeney et a1. Jan. 2, 1934 Mason et a1. Apr. 27, 1943 FOREIGN PATENTS Country Date Great Britain of 1855 Great Britain of 1857 Great Britain Aug. 6, 1931 Australia Oct. 19, 1939 France Feb. 12, 1917 France Feb, 3, 1928 

1. A COMPOSITION OF MATTER CONSISTING OF WOODY MATERIAL DERIVED FROM THE SHIVES OF UNRETTED BAST FIBER PLANTS CONTAINING SUBSTANTIALLY ALL THE NATURAL CONTENT OF PENTOSAN AND FURFUAL-YIELDING MATERIAL AND PRESSED UNDER HEATING INTO THE FORM OF AN INSULATING AND BUILDING BOARD. 